1. Field of the Invention
The present invention relates to a novel cationic dye represented by the Formula I, which may be useful for dyeing synthetic fibrous materials composed of an acid modified polyacrylonitrile or a copolymer thereof, polyamide or polyester: ##STR5## wherein the group ##STR6## represents an unsubstituted or 4 and/or 5-substituted thiazole ring, or an unsubstituted or 6-substituted benzothiazole ring, B represents an indolyl group represented by the formula ##STR7## wherein R.sub.1 represents an alkyl having 1 to 4 carbon atoms, an aralkyl or an aryl, said aryl may have an alkyl having 1 to 2 carbon atoms, an alkoxy having 1 to 2 carbon atoms, a halogen, cyano or nitro, and R.sub.2 represents hydrogen, an alkyl having 1 to 4 carbon atoms, an alkoxyalkyl, an acyloxyalkyl, a haloalkyl, a cyanoalkyl or a carbamoylalkyl, or an anilino group represented by the formula ##STR8## wherein R.sub.3 represents hydrogen, an alkyl having 1 to 2 carbon atoms, an alkoxy having 1 to 2 carbon atoms, a halogen, cyano or nitro, R.sub.4 and R.sub.5 represent individually an alkyl having 1 yo 4 carbon atoms, an alkoxyalkyl, an acyloxyalkyl, a cycloalkyl, an aralkyl or an aryl, said aryl may have an alkyl having 1 to 2 carbon atoms, an alkoxy having 1 to 2 carbon atoms, a halogen, cyano or nitro, and n is an integer of 1 or 2, R represents an alkyl having 1 to 4 carbon atoms, and Z.sup.- is an anion.
More particularly, the present invention relates to blue cationic dyes represented by the formula ##STR9## and red cationic dyes represented by the formula ##STR10## wherein R, R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and ##STR11## have the same significances as defined above.
2. Description of the Prior Art
Some of p-aminophenol thiazoliumazo type blue cationic dyes similar to the dyes having above formula (II) are disclosed in Japanese Patent Publications Nos. 14,337/61, 14,934/62, and 14,935/62, and it is disclosed that they have excellent color values for polyacrylonitrile fibers and the fibers dyed have excellent fastness to sunlight and cleaning. However, these known dyes have the fault that when a concentrated solution of the dye is allowed to stand at room temperature, the dye is crystallized, and further, when the dye solution is used for printing, specks are apt to form owing to the poor solubility of the dye.
Moreover, these known dyes have generally such faults that they are so poor in heat resistance, particularly steam heat resistance, that they are apt to be discolored by heat treatment. For improving these faults, the dyes as described in Japanese Patent Publication No. 5659/68 are proposed. However, if the heat resistance of dyes is improved, the solubility of the dye is greatly reduced in general, and the affinity thereof becomes too strong, whereby the dyeing velocity becomes so high that a uniform dyeing cannot be given.
The novel dyes of this invention represented by the above formula (II) have been discovered as the result of the inventor's investigation for overcoming the faults mentioned above. That is, the present dyes are excellent in solubility at low temperature as well as in fastness to steam, and also can provide uniformly dyed articles because they have a quite proper dyeing velocity in practice. Furthermore, the articles dyed by the present dyes have excellent fastness to sunlight and cleaning.
Some of the thiazole type red cationic dyes similar to the red cationic dyes represented by the above formula (III) are disclosed in Japanese Patent Publication No. 6933/59. These known dyes, however, have such faults that the affinity to fibers is too strong, whereby the dyeing velocity becomes so high that a uniform dyeing cannot be given.
The present inventors have investigated overcoming these faults and as a result have found that the dyes of the formula (III) have a quite proper dyeing velocity to give a uniform dyeing, and have less phototropy compared with the known dyes having the formula similar to that of the present dyes (III).
Thus, the present dyes of the formula (I) have so proper a dyeing velocity that they may be useful for dyeing fibrous materials to middle and light colors and are particularly useful as so-called three-primary color dyes. Moreover, the present dyes of the formula (I) are stable in hot water and in wet and dry heating on fibrous materials. Furthermore, as they have excellent water solubility, a concentrated aqueous solution thereof can be readily prepared, without precipitation, and therefore the dyes are suitable for printing.